Added ability to scope the slug

.gitignore

@@ -1,3 +1,4 @@
 *.sw?
 .DS_Store
-coverage
+coverage
+.rvmrc

lib/slug/slug.rb

@@ -8,24 +8,30 @@ module ClassMethods
     #
     # Options:
     # * <tt>:column</tt> - the column the slug will be saved to (defaults to <tt>:slug</tt>)
-    # * <tt>:validate_uniquness_if</tt> - proc to determine whether uniqueness validation runs, same format as validates_uniquness_of :if
+    # * <tt>:validate_uniqueness_if</tt> - proc to determine whether uniqueness validation runs, same format as validates_uniquness_of :if
+    # * <tt>:validate_uniqueness_scope</tt> - the column to scope the uniqueness check to
     #
     # Slug will take care of validating presence and uniqueness of slug.
 
     # Before create, Slug will generate and assign the slug if it wasn't explicitly set.
     # Note that subsequent changes to the source column will have no effect on the slug.
     # If you'd like to update the slug later on, call <tt>@model.set_slug</tt>
     def slug source, opts={}
-      class_inheritable_accessor :slug_source, :slug_column
+      class_inheritable_accessor :slug_source, :slug_column, :slug_scope
       include InstanceMethods
 
       self.slug_source = source
 
       self.slug_column = opts.has_key?(:column) ? opts[:column] : :slug
 
       uniqueness_opts = {}
-      uniqueness_opts[:if] = opts[:validate_uniqueness_if] if opts.key?(:validate_uniqueness_if)
+      uniqueness_opts[:if]    = opts[:validate_uniqueness_if]     if opts.key?(:validate_uniqueness_if)
 
+      if opts.key?( :validate_uniqueness_scope )
+        uniqueness_opts[:scope] = self.slug_scope = opts[:validate_uniqueness_scope]
+      end
+
+
       validates                 self.slug_column, :presence => { :message => "cannot be blank. Is #{self.slug_source} sluggable?" }
       validates                 self.slug_column, :uniqueness => uniqueness_opts
       validates                 self.slug_column, :format => { :with => /^[a-z0-9-]+$/, :message => "contains invalid characters. Only downcase letters, numbers, and '-' are allowed." }
@@ -113,7 +119,7 @@ def assign_slug_sequence
 
     # Returns the next unique index for a slug.
     def next_slug_sequence
-      last_in_sequence = self.class.where("#{self.slug_column} LIKE ?", self[self.slug_column] + '%').order("CAST(REPLACE(#{self.slug_column},'#{self[self.slug_column]}-','') AS UNSIGNED) DESC").first
+      last_in_sequence = find_last_in_sequence
       if last_in_sequence.nil?
         return 0
       else
@@ -122,5 +128,14 @@ def next_slug_sequence
         return current + 1
       end
     end
+
+    def find_last_in_sequence  
+      if self.slug_scope.present?
+
+        self.class.where("#{self.slug_column} LIKE ? and #{self.slug_scope} = ?", self[self.slug_column] + '%', self[self.slug_scope]).order("CAST(REPLACE(#{self.slug_column},'#{self[self.slug_column]}-','') AS UNSIGNED) DESC").first
+      else        
+        self.class.where("#{self.slug_column} LIKE ?", self[self.slug_column] + '%').order("CAST(REPLACE(#{self.slug_column},'#{self[self.slug_column]}-','') AS UNSIGNED) DESC").first
+      end
+    end
   end
 end

slug.gemspec

@@ -29,7 +29,7 @@ Gem::Specification.new do |s|
      "test/models.rb",
      "test/schema.rb",
      "test/test_helper.rb",
-     "test/test_slug.rb"
+     "test/slug_test.rb"
   ]
   s.homepage = %q{http://github.com/bkoski/slug}
   s.rdoc_options = ["--charset=UTF-8"]
@@ -40,7 +40,7 @@ Gem::Specification.new do |s|
     "test/models.rb",
      "test/schema.rb",
      "test/test_helper.rb",
-     "test/test_slug.rb"
+     "test/slug_test.rb"
   ]
 
   if s.respond_to? :specification_version then

test/models.rb

@@ -24,4 +24,15 @@ class Event < ActiveRecord::Base
   def title_for_slug
     "#{title}-#{location}"
   end
+end  
+
+class Portfolio < ActiveRecord::Base
+  has_many :projects
+end
+
+class Project < ActiveRecord::Base
+
+  belongs_to :portfolio
+  slug :title, :validate_uniqueness_scope => :portfolio_id
+
 end

test/schema.rb

@@ -25,6 +25,15 @@
     t.column "title", "string"
     t.column "location", "string"
     t.column "slug", "string"
+  end 
+
+  create_table "portfolios", :force => true do |t|    
+  end
+
+  create_table "projects", :force => true do |t|
+    t.column "title", "string"
+    t.column "slug", "string"
+    t.column "portfolio_id", "integer"
   end
 
 end

test/test_slug.rb → test/slug_test.rb

@@ -1,8 +1,9 @@
-require File.dirname(__FILE__) + '/test_helper'
+# encoding: UTF-8
+require 'test_helper'
 
-class TestSlug < Test::Unit::TestCase
+class SlugTest < Test::Unit::TestCase
 
-  def setup
+  def setup 
     Article.delete_all
     Person.delete_all
   end
@@ -44,7 +45,6 @@ def setup
   should "set validation error if source column is empty" do
     article = Article.create
     assert !article.valid?
-    require 'ruby-debug'
     assert article.errors[:slug]
   end
 
@@ -245,6 +245,43 @@ def setup
       article_13 = Article.create!(:headline => 'latest from lybia')
       assert_equal 'latest-from-lybia-12', article_13.slug
     end    
+  end 
+
+  context "uniqueness with scope" do
+
+    setup do
+      @portfolio_1 = Portfolio.create!
+      @portfolio_2 = Portfolio.create!
+    end
+
+    context "with same project name in @portfolio_1 and @portfolio_2" do
+
+      setup do
+        @project_1 = @portfolio_1.projects.create!(:title => "My Project")
+        @project_2 = @portfolio_2.projects.create!(:title => "My Project")
+      end
+
+      should "set @project_1 slug to my-project" do
+        assert_equal "my-project", @project_1.slug
+      end
+
+      should "set @project_2 slug to my-project" do
+        assert_equal "my-project", @project_2.slug
+      end     
+
+      context "with the same project name in the same portfolio" do
+        setup do
+          @project_3 = @portfolio_1.projects.create!(:title => "My Project")
+        end
+
+        should "set @project_3 slug to my-project-2" do
+          assert_equal "my-project-1", @project_3.slug
+        end
+      end
+
+    end
+
+
   end
 
 end